One of the important use cases for UAVs is surveillance in all its forms. Small, cheap aircraft can cover a lot of area, carry a lot of different sensors, and swoop in to obtain very close up information. In some cases, a human can directly control the aircraft (as in selfie cams and drone racing), but for many cases the UAV needs to be substantially autonomous.
Furthermore, remote observation generally needs long, slow flights, rather than short, fast ones. Range and flight duration are critical.
Remote sensing by UAVs is ideal for many kinds of environmental research, especially in remote areas such as deserts, oceans, or polar regions. A fleet of (inexpensive) UAVs can multiply the view of a single (very expensive) scientist by orders of magnitude, measuring a broad area, and identifying points of interest for detailed investigation.
This summer a group of researchers from ETH and the AtlantikSolar company have demonstrated a UAV that continuously monitored glaciers in Greenland. The Sun2ice is solar powered, so it charges its batteries as long as the sun is shining. In the polar summer, there is essentially 24 hour sunlight, so the UAV has power to fly continuously for months, at least in principle. Like other solar powered aircraft and boats, the AtlantikSolar needs not fuel and should be capable of extremely long missions.
Of course, flying over Greenland is difficult for any aircraft, and flying a small UAV continuously over remote and rugged glaciers is very challenging. The aircraft must deal with high winds and cold temperatures, even in good weather. With no pilot on board, the control systems must be highly automated.
The UAV must navigate over uninhabited territory, far from the humans back at base. It has to stay on station to collect data continuously, with little help from people. Magnetic compasses don’t work on Greenland, and continuous daylight means that celestial navigation is not possible either.
The researchers also had to deal with take off and landing from a remote field station. The video shows the UAV being delivered to its launch point via dogsled—Pleistocene technology deploying twenty first century technology. The test flights were successful, though flying time was less than a full day.
“Flying an experimental solar-powered UAV as AtlantikSolar in Arctic conditions is very challenging due to the narrow sun angle, extreme climatic conditions, the weakness of the magnetic field used for the compass, and the absence of smooth grass-covered terrain to land a fragile airplane.”
This technology is ideal for intense observation of glaciers and other natural phenomena. The UAV flies low enough to obtain high resolution images, and if it can stay on station, can provide updated data every hour or less. The UAV is cheaper than a satellite, and even than a piloted aircraft. It would be possible to deploy a fleet of UAVS to monitor a glacier or volcano in great detail for substantial periods.
- Philipp Oettershagen, Amir Melzer, Thomas Mantel, Konrad Rudin, Thomas Stastny, Bartosz Wawrzacz, Timo Hinzmann, Stefan Leutenegger, Kostas Alexis, and Roland Siegwart, Design of small hand-launched solar-powered UAVs: From concept study to a multi-day world endurance record flight. Journal of Field Robotics, 34 (7):1352-1377, 2017. http://dx.doi.org/10.1002/rob.21717